Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), C. P.486, Belo Horizonte, MG, 30161-970, Brasil.
Programa de Pós-Graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais (PUC Minas), Belo Horizonte, MG, Brasil.
Fish Physiol Biochem. 2012 Dec;38(6):1709-1719. doi: 10.1007/s10695-012-9668-3. Epub 2012 Jun 12.
River damming and building of hydroelectric power plants interrupt the reproductive migration routes and change the major physicochemical parameters of water quality, with drastic consequences for populations of migratory fishes. The goal of this study was to evaluate proliferation and cell death during spermatogenesis and serum profiles of sex steroids in Prochilodus argenteus, from the São Francisco River, downstream from the Três Marias Dam. A total of 257 adult males were caught quarterly during a reproductive cycle in two sites: the first 34 km of the river after the dam (site 1) and the second 34-54 km after the dam (site 2), after the confluence with a tributary, the Abaeté River. Seasonal changes in the testicular activity associated with morphometric analyses of germ cells as well as proliferation and testicular apoptosis support a more active spermatogenesis in fish from site 2, where higher levels of sex steroids and gonadosomatic index (GSI) were also found. In site 1, fish presented low serum levels of testosterone, 17β-estradiol and 17α-hydroxyprogesterone and a low GSI during gonadal maturation. Spermatogonial proliferation (PCNA) and apoptosis (TUNEL) were more elevated in fish from site 1, but spermatocytes were mainly labelled in fish from site 2. Overall, these data demonstrate changes in testicular activity and plasma sex steroids in a neotropical teleost fish living downstream from a hydroelectric dam, supplying new data on fish reproduction in regulated rivers. Moreover, morphometric analyses associated with sex steroids profiles provide reliable tools to assess fish spermatogenesis under environmental stress conditions.
建坝和修建水电站会阻断洄游鱼类的生殖洄游路线，并改变水质的主要理化参数，对洄游鱼类种群产生巨大影响。本研究旨在评估在受三马林达大坝影响的圣弗朗西斯科河下游，源自银脂鱼 Prochilodus argenteus 的精子发生过程中的增殖和细胞死亡，以及血清中性类固醇的水平。在一个生殖周期内，我们每季度在两个地点捕捞了 257 条成年雄性银脂鱼：大坝下游的前 34 公里（地点 1）和大坝下游的后 34-54 公里（地点 2），此处与一条支流 Abaeté 河交汇。与精母细胞形态计量分析相关的睾丸活动的季节性变化以及增殖和睾丸细胞凋亡表明，地点 2 的精子发生更为活跃，此处还发现了更高水平的性类固醇和性腺指数（GSI）。在地点 1，鱼类在性腺成熟期间表现出低水平的血清睾酮、17β-雌二醇和 17α-羟孕酮，以及低的 GSI。地点 1 的鱼类精原细胞增殖（PCNA）和凋亡（TUNEL）水平更高，但精母细胞主要在地点 2 的鱼类中被标记。总的来说，这些数据表明，在受水电站影响的新热带鱼类的睾丸活动和血浆中性类固醇发生了变化，为调控河流中的鱼类繁殖提供了新的数据。此外，与性类固醇水平相关的形态计量分析为评估鱼类在环境胁迫条件下的精子发生提供了可靠的工具。
